Growth of vertically self-organized InGaAs quantum dots with narrow inhomogeneous broadening

We have fabricated vertically self-organized multiple sets of In0.6Ga0.4As quantum dots (QDs) on GaAs (001) that combines the concepts of variable amo unt deposition and shape stabilization and size equalization of QDs. The in homogeneous broadening of optical emission from these dots reached a record low value of 18.4 meV at a wavelength of similar to 1185 nm (4 K). The see d layer and the second dot layer have essentially the same dot density of s imilar to 250 mu m(-2) due to the high degree of dot vertical alignment. Th e deposition amount for the second dot layer was selected to be 9 monolayer s, which resulted in dots with convergent lateral size (similar to 62 nm) a nd stabilized facets, close to {011}. The third layer, with the same amount of InGaAs as the second layer, had a dot density of similar to 350 mu m(-2 ), an average lateral dot size of similar to 71 nm, an average dot height o f similar to 11 nm, and shallower side facets close to {023}. (C) 2000 Amer ican Institute of Physics. [S0003-6951(00)05521-2].